Asynchronous
REST/Comet API

Overview

The Everyware Device Cloud (EDC) platform provides support
for Asynchronous REST/Comet APIs. This solution allows client applications to
use HTTP and REST to subscribe on topics of interest and have matching data
being streamed to them in real-time. Together with the ability of publishing
data through the REST API described in the previous section, this completes the
Everyware Device Cloud (EDC) offering of a full MQTT to HTTP bridge.

The following example illustrates how the EDC Comet API can
be used to receive streaming data using REST APIs.

Using the Comet API

In your workspace under edc-comet/src/main/webapp, open
the file index.html in your
favorite text editor. This file follows the data model used in the edc-java-client example and assumes that
your data is published under the sample/data
topic and contains metrics named int, dbl,
flt.

Change the following lines of code to use your Everyware
Cloud Username, Password, and Account and save your changes.

Using the Firefox or Safari browser, open index.html. (Note: this does not work
with Internet Explorer.) Click on the Subscribe button shown in the following screen
captue.

In Eclipse, run the edc-java-client
application by selecting the green Run button in the Launch toolbar
to make a connection to the Cloud and start publishing data. The data displays
in real-time as shown in the following screen capture.

See the full JavaScript code for details on the API
operation.

Next Steps

This is a very simple example to show the Comet/streaming
capabilities of the EDC platform. You are encouraged to package this example
into a proper Web application before deploying it into production.